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FFmpeg/libavutil/x86/lls_init.c
Ganesh Ajjanagadde 5989add4ab lavu/x86/lls: add fma3 optimizations for update_lls
This improves accuracy (very slightly) and speed for processors having
fma3.

Sample benchmark (fate flac-16-lpc-cholesky, Haswell):
old:
5993610 decicycles in ff_lpc_calc_coefs,      64 runs,      0 skips
5951528 decicycles in ff_lpc_calc_coefs,     128 runs,      0 skips

new:
5252410 decicycles in ff_lpc_calc_coefs,      64 runs,      0 skips
5232869 decicycles in ff_lpc_calc_coefs,     128 runs,      0 skips

Tested with FATE and --disable-fma3, also examined contents of
lavu/lls-test.

Reviewed-by: James Almer <jamrial@gmail.com>
Reviewed-by: Henrik Gramner <henrik@gramner.com>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
2016-01-15 16:46:13 -05:00

46 lines
1.6 KiB
C

/*
* linear least squares model
*
* Copyright (c) 2013 Loren Merritt
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/lls.h"
#include "libavutil/x86/cpu.h"
void ff_update_lls_sse2(LLSModel *m, const double *var);
void ff_update_lls_avx(LLSModel *m, const double *var);
void ff_update_lls_fma3(LLSModel *m, const double *var);
double ff_evaluate_lls_sse2(LLSModel *m, const double *var, int order);
av_cold void ff_init_lls_x86(LLSModel *m)
{
int cpu_flags = av_get_cpu_flags();
if (EXTERNAL_SSE2(cpu_flags)) {
m->update_lls = ff_update_lls_sse2;
if (m->indep_count >= 4)
m->evaluate_lls = ff_evaluate_lls_sse2;
}
if (EXTERNAL_AVX_FAST(cpu_flags)) {
m->update_lls = ff_update_lls_avx;
}
if (EXTERNAL_FMA3(cpu_flags) && !(cpu_flags & AV_CPU_FLAG_AVXSLOW)) {
m->update_lls = ff_update_lls_fma3;
}
}